page_title: Hurricane Isabel
section_title: Meteorological history
hierarchical_section_title: Hurricane Isabel / Meteorological history
caption_attribution_description: The MODIS instrument onboard NASA's Aqua satellite captured this true-color image of Hurricane Isabel on September 14, 2003 at 17:55 UTC. In this image Isabel is located about 400 miles north of Puerto Rico and is packing maximum sustained winds near 155 mph.
context_page_description: Hurricane Isabel was the strongest Atlantic hurricane since Mitch, and the deadliest, costliest, and most intense hurricane in the 2003 Atlantic hurricane season. The ninth named storm, fifth hurricane, and second major hurricane of the season, Isabel formed near the Cape Verde Islands from a tropical wave on September 6, in the tropical Atlantic Ocean. It moved northwestward, and within an environment of light wind shear and warm waters, it steadily strengthened to reach peak winds of 165 mph on September 11. After fluctuating in intensity for four days, during which it displayed annular characteristics, Isabel gradually weakened and made landfall on the Outer Banks of North Carolina, with winds of 105 mph on September 18. Isabel quickly weakened over land and became extratropical over western Pennsylvania on the next day. On September 20, the extratropical remnants of Isabel were absorbed into another system over Eastern Canada.
  In North Carolina, the storm surge from Isabel washed out a portion of Hatteras Island to form what was unofficially known as Isabel Inlet. Damage was greatest along the Outer Banks, where thousands of homes were damaged or even destroyed.
context_section_description: A tropical wave moved off the western coast of Africa on September 1. An area of low pressure associated with the wave moved slowly westward, and its convection initially appeared to become better organized. On September 3, as it passed to the south of the Cape Verde islands, organization within the system degraded, though convection increased the next day. The system gradually became better organized, and Dvorak classifications began early on September 5. Based on the development of a closed surface circulation, it is estimated the system developed into Tropical Depression Thirteen early on September 6. Hours later, it intensified into Tropical Storm Isabel, though operationally the National Hurricane Center did not begin issuing advisories until 13 hours after it first developed.
  Located within an area of light wind shear and warm waters, Isabel gradually organized as curved bands developed around a circular area of deep convection near the center. It steadily strengthened as it moved to the west-northwest, and Isabel strengthened to a hurricane on September 7 subsequent to the development of a large, yet ragged eye located near the deepest convection. The eye, overall convective pattern, and outflow steadily improved in organization, and deep convection quickly surrounded the 40-mile (60 km)-wide eye. Isabel intensified on September 8 to reach major hurricane status while located 1,300 miles (2,100 km) east-northeast of Barbuda. On September 9, Isabel reached an initial peak intensity of 135 mph (215 km/h) for around 24 hours, a minimal Category 4 hurricane on the Saffir–Simpson Hurricane Scale.
  Early on September 10, the eyewall became less defined, the convection near the eye became eroded, and northeasterly outflow became slightly restricted. As a result, Isabel weakened slightly to a Category 3 hurricane. The hurricane turned more to the west due to the influence of the Bermuda-Azores High. Later on September 10, Isabel restrengthened to a Category 4 hurricane after convection deepened near the increasingly organizing eyewall. The hurricane continued to intensify, and Isabel reached its peak intensity of 165 mph (270 km/h) on September 11, a Category 5 hurricane on the Saffir–Simpson Hurricane Scale. Due to an eyewall replacement cycle, Isabel weakened slightly, though it retained Category 5 status for 24 hours. As Isabel underwent another eyewall replacement cycle, outflow degraded in appearance and convection around the eye weakened, and early on September 13, Isabel weakened to a strong Category 4 hurricane. A weakness in the ridge to its north allowed the hurricane to turn to the west-northwest. After completing the replacement cycle, the hurricane's large 40 mile (65 km) wide eye became better defined, and late on September 13, Isabel re-attained Category 5 status. During this time, Isabel attained annular characteristics, becoming highly symmetrical in shape and sporting a wide eye. Hurricane Isabel also displayed a "pinwheel" eye, a rare feature that is found in some annular tropical cyclones. A NOAA Hurricane Hunter Reconnaissance Aircraft flying into the hurricane launched a dropsonde which measured an instantaneous wind speed of 233 mph (375 km/h), the strongest instantaneous wind speed recorded in an Atlantic hurricane. Cloud tops warmed again shortly thereafter, and Isabel weakened to a strong Category 4 hurricane early on September 14. Later that day, it re-organized, and for the third time, Isabel attained Category 5 status while located 400 miles (650 km) north of San Juan, Puerto Rico.
  Cloud tops around the center warmed again early on September 15, and Isabel weakened to a Category 4 hurricane. Later that day, the inner core of deep convection began to deteriorate, while the eye decayed in appearance. As a ridge to its northwest built southeastward, it resulted in Isabel decelerating as it turned to the north-northwest. Increasing vertical wind shear contributed in weakening the hurricane further, and Isabel weakened to a Category 2 hurricane on September 16, while located 645 miles (1035 km) sout
caption: Hurricane Isabel displaying annular characteristics on September 14, as a powerful Category 5 hurricane
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